Rayburn Heatranger 480GB, Servicing Instructions

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When the programmer switches off the BOILER channel
then the water circulating pump will be switched off. If
during the period shortly after this the residual heat in the
appliance causes the water temperature in the boiler to
rise above 85˚C then the pump overrun thermostat will
change-over. This will switch on the circulating pump.
If during a normal programmer COOKER ‘ON’ period the
boiler flow temperature rises above 65˚C then the pump
overrun thermostat operates and switches on the pump
until the overrun thermostat switches back.
BOILER
This thermostat is a safety cut-out device which is
intended to operate if the other controls fail. This control
will “lock-out” and switches everything off except for the
programmer clock and the “Pump Overrun” facility.
This thermostat has to be manually reset once the
temperature has cooled down.
COOKER
This thermostat is a safety cut-out device which operates
if the control thermostat fails. This device automatically
resets.
Electrical Controls
20
PUMP OVERRUN
FACILITY
OVERHEAT SAFETY
THERMOSTATS